The present disclosure relates to additive manufacturing systems and processes for printing or otherwise building three-dimensional (3D) parts with layer-based, additive manufacturing techniques. In particular, the present disclosure relates to systems and methods for building 3D parts with an additive manufacturing system that uses a plurality of directed energy beams to selectively sinter or melt layers of powder-based material in a layer-by-layer manner.
Additive manufacturing systems are used to build 3D parts from digital representations of the 3D parts (e.g., AMF and STL format files) using one or more additive manufacturing techniques. Examples of commercially available additive manufacturing techniques include extrusion-based techniques, ink jetting, selective laser sintering, powder/binder jetting, electron-beam melting, and stereolithographic processes. For each of these techniques, the digital representation of the 3D part is initially sliced into multiple horizontal layers. For each sliced layer, a tool path is then generated, which provides instructions for the particular additive manufacturing system to form the given layer.
For example, in an extrusion-based additive manufacturing system, a 3D part may be printed from a digital representation of the 3D part in a layer-by-layer manner by extruding a flowable part material. The part material is extruded through an extrusion tip carried by a print head of the system, and is deposited as a sequence of roads on a substrate in an x-y plane. The extruded part material fuses to previously deposited part material, and solidifies upon a drop in temperature. The position of the print head relative to the substrate is incremented along a z-axis (perpendicular to the x-y plane), and the process is repeated to form a 3D part resembling the digital representation.
In another example, in a stereolithography-based additive manufacturing system, a 3D part may be printed from a digital representation of the 3D part in a layer-by-layer manner by tracing a laser beam across a vat of photocurable resin. For each layer, the laser beam draws a cross-section for the layer on the surface of the liquid resin, which cures and solidifies in the drawn pattern. After the layer is completed, the system's platform is lowered by a single layer increment. A fresh portion of the resin may then recoat the previous layer, and the laser beam may draw across the fresh resin to pattern the next layer, which joins the previous layer. This process may be repeated for each successive layer. Afterwards, the uncured resin may be cleaned, and the resulting 3D part may undergo subsequent curing.
In yet another example, in a selective laser sintering (SLS) based additive manufacturing system, a 3D part may be printed from a digital representation of the 3D part in a layer-by-layer manner by tracing a laser beam across a part bed containing a layer of powder-based build material. For each layer, the laser beam draws a cross-section for the layer on the surface of the powder layer, which sinters or melts and solidifies the drawn pattern. After the layer is completed, the system's platform or part bed is lowered by a single layer increment. A fresh layer of powder-based build material may then be applied to cover the previous layer, and the laser beam may draw across the fresh layer of powder to pattern the next layer, which is also sufficiently joined to the previous layer. This process may be repeated for each successive layer. Afterwards, the powder not processed by the laser is simply brushed away or removed when the 3D part is removed from the part bed and the resulting 3D part may undergo subsequent processing or cleaning.